thode Champenoise Process on Aroma of Four

Transcription

1 thode Champenoise Process on Aroma of Four V. vinifera Varieties Effect of M C. DE LA PRESA-OWENS ~, P. SCHLICH 2, H. D. DAVIES 3, and A. C. NOBLE 4. To characterize the changes in aroma resulting from the M#thode Champenoise process, 28 base wines and their corresponding sparkling wines were profiled by descriptive analysis. The base wines were made from Chardonnay, Pinot blanc, Pinot Meunier, and Pinot noir grapes grown in Anderson Valley, Carneros District,, and Valley. Intensities of seven aroma attributes were rated in base wines and sparkling wines separately. Principal Component Analyses (PCA) of the base wine data separated the white from red varietal wines, whereas the PCA of the sparkling wines did not cluster wines by region or variety. When differences in intensity ratings between each sparkling wine and its corresponding base wine were analyzed by PCA, the first dimension separated the white from red varietal wines. This pattern resulted primarily from the larger increase in citrus and apple intensity in red varietals and in vanilla/butter aroma in whites during the 8 months on yeast following the secondary fermentation. KEY WORDS: base wine, sparkling wine, flavor, sensory, descriptive analysis The character of bottle-fermented sparkling wines (M~thode Champenoise) is primarily influenced by grape variety, vineyard location, and yeast autolysis during aging. The effect on wine composition of yeast autolysis during aging [2] has been studied, as have factors influencing yeast growth such as the fermentation condition of the yeast inoculum [5] as well as bottle pressure, which affects the growth rate of yeast [6]. With the exception of two studies, sparkling sensory evaluations have only examined quality or preference ratings of base wines [2,4] and sparkling wines [4,5,9,,3,6]. Using analytical sensory procedures, the sensory effects of varietal composition [7] and geographical parameters [0] were monitored in base wines later used in sparkling wine production. However, no investigations have profiled the changes which occur during secondary fermentation and subsequent aging on the yeast in sparkling wines made by the M~thode Champenoise process. The objective of this research was to quantitatively monitor the effect of the secondary fermentation process on aroma of the four major varietal wines used in sparkling wine production. Materials and Methods Wines: Pinot noir, Chardonnay, Pinot Meunier, and Pinot blanc base wines were made by the participating wineries from vineyards in five different regions in California (Table ). Each wine was made from a single Vitis vinifera cultivar using "free run" juice with,4dept. Viticulture & Enology, University of California, Davis, CA 9566 (FAX ; acnoble@ucdavis.edu, phone ); 2 Inst. Nat. Rech.Agro., 2000 Dijon, France; 3 Winery, Calistoga, CA. *Corresponding author: [Fax: ; <acnoble@ucdavis.edu>]. Acknowledgments: This research was funded by the participating wineries, and grants from the Spanish Government (CPO), the Adolf Heck foundation (HDD) and NATO (PS). Manuscript submitted for publication 26 September 997. Copyright 998 by the American Society for Enology and Viticulture. All rights reserved. 289 minimal contact with grape skins or seeds. Wines were fermented in stainless steel and had not undergone malolactic fermentation. After being transferred to the university at the end of fermentation, wines were coldstabilized, and sulfur dioxide was added, prior to bottling. For preparation of the sparkling wines, 25 ml/l inverted sugar was added to provide 6.25 Atm pressure Table. Vineyard and winery of original and variety of wines. Variety Winery Vineyard location Chardonnay Mumm Anderson Valley Roederer Estate Anderson Valley Scharfenberger Anderson Valley Domaine Carneros Carneros-Napa Gloria Ferrer Carneros-Sonoma Mumm Mumm Iron Horse Jordon Korbel Pinot blanc Piper Sonoma Alexander Valley Domaine Carneros Carneros-Napa Pinot Meunier Mumm Carneros-Napa Jordon Pinot noir Mumm Anderson Valley Roederer Estate Anderson Valley Domaine Carneros Carneros-Napa Gloria Ferrer Carneros-Sonoma Korbel Mumm Iron Horse Santa Maria

2 290- DE LA PRESA-OWENS et al. with Red Star Premier Cuv6e yeast (Universal Foods Corporation, Milwaukee, WI), and 0.7 ml/l bentonite solution (Clarificant S, Pechiney Cork & Seal Co., Vallejo, CA). Wines were stored at 7 C until the secondary fermentation was completed, then held at 0 C. After 8 months bottle-aging, the sparkling wines were riddled, disgorged, and 20 ppm of SO 2 added. Sensory protocol: Preliminary evaluation of the wines indicated that few differences among the wines were found in taste, while there were large differences in aroma. Consequently, descriptive analyses of wine aroma were performed. The base wines were evaluated in February 995 and the sparkling wines in November of 996 by two different panels. Twenty-one judges (2 males and 9 females, 8 to 40 years of age) participated in the base wine evaluation, while 7 (3 males and 4 females, 22 to 47 years of age) were on the sparkling wine panel. wine judges were trained for two weeks prior to formal testing, while the sparkling wine judges were trained for four weeks. At each training session, aroma standards were presented with selected wines from the experiment. For the last week of training, the seven aroma attributes which had been selected by the individual panels were rated in two practice sessions, using the same procedures as in the formal sessions. The composition of the reference standards which defined these aroma notes are given in Table 2. Formal sessions: Formal evaluations were conducted in individual booths at 20 C to 22 C under red light to mask color differences. Reference standards which were evaluated prior to each session were available for subsequent evaluation as necessary. Distilled water was provided for sniffing between wines. Twenty-five milliliters of base wine or 40 ml sparkling wines were presented in coded, 70-mL, tulip-shaped wine glasses covered with plastic lids. wines were evaluated at room temperature (2 C _+ 2 C ). wines were cooled to 0 C before being poured. The sparkling wines were held uncovered for five minutes after being poured to stabilize the level of CO 2, then covered and served. Six or seven base wines were presented per session in a different random order to each judge for each of the duplicate evaluations. For the triplicate evaluation of the sparkling wines, the presentation order for each judge and each replicate was balanced for position and first order carry over effect using William's Latin Squares design [7]. Seven sparkling wines per session were evaluated monadically (one at a time) to standardize evolution of carbon dioxide. For both wine types, at each session judges evaluated the standards and then scored the intensity of each term on a category scale where 0 = no, = "low", and 9 = "high". Data analysis: All descriptive data was analyzed using SAS System for Windows, Version 6. (SAS Institute Inc., Cary, NC 994). For base and sparkling wines separately, intensity ratings were analyzed by mixed model analysis of variance (ANOVA) with judges considered a random effect. A mixed model analysis of variance (ANOVA), where both grape variety and wine type (base/sparkling) were treated as fixed effects, where wines nested within variety were considered as a random effect was also performed. Principal component analysis (PCA) of the covariance matrix of judge average ratings for each wine was performed for each wine type separately and on base and sparkling wines together. To illustrate the effect of the secondary fermentation on the four varietals, a PCA was run on the difference in intensity ratings between each base and sparkling wine. To compare the base and sparkling aroma Table 2. Composition of aroma reference standards for base and sparkling wine descriptive analysis. Attribute Citrus Tropical fruit Apple/Pear Floral Vanilla/Butter Peach/Melon Berry Honey Toasty Tea/Tobacco Experiment Composition in 500 ml Thompson Seedless wine (base) or 30 ml Chardonnay wine (sparkling) 5 g grated orange + 5 g grated lemon peels; 30 me fresh orange, 5 ml fresh lemon, 5 me fresh grapefruit, 5 ml fresh lime juice.5 ml lemon juice + 2 ml orange juice + ml pineapple juice 5 ml imitation banana flavor, 5 ml imitation coconut flavor + 34 ml canned pineapple juice 8 g coconut, 3 g Koolaid tropical fruit mix,.5 g banana + 5 ml frozen pear concentrate chopped green apple, chopped Bartlett pear + 5 ml frozen pear concentrate 5 g chopped green apple + 6 g chopped red apple ml phenyl ethyl alcohol, 0 g rose petals 0. ml linalool, ml phenethyl alcohol 2 chopped caramel cubes, 2 drops butter extract, 5 g vanillin g sweet butter + 2 g caramelized sugar, ml pure vanilla extract 30 ml frozen peach concentrate, chopped canned peach, 30 g fresh cantaloupe 7 g peach pulp, 7 g chopped melon, 6 g chopped pear 6 fresh strawberries, 6 frozen raspberries + 6 canned black cherries 7 g blackberry, 5 g strawberry 3.5 g honey (3 mm x 3 mm) piece American white oak toasted chip, 0. g toasted almonds 3 g English tea, 0. g cigarette tobacco

3 EFFECT OF ME-THODE CHAMPENOISE ON AROMA m 29 configurations, the RV coefficient, a generalized correlation coefficient, and the analytical generalized permutation test of the RV value, were calculated. The value of this coefficient is expressed as normal deviation from the null hypothesis permitting a statistical estimate of the fit [8]. Results and Discussion wines: All terms but tropical fruit (p < 0.0) varied highly significantly across the 28 base wines (p < 0.00). From a principal component analysis (PCA) of these mean ratings, the first PC separated base wines high in vanilla/butter versus those high in floral, citrus and apple (Fig. ). wines made from white grape varieties, Chardonnay and Pinot blanc, were clustered together and were generally higher in floral, citrus, and apple. The red varietal wines, Pinot noir and Pinot Meunier, were higher in berry and vanilla/butter terms and, with the exception of two wines, were separated from the white base wines. Visual inspection of Figure data failed to show clustering by region or even by winery. wines: The sparkling wines varied significantly in five terms: vanilla/butter (p < 0.00), peach/melon and apple (p < 0.0), tropical fruit and citrus (p < 0.05). PCA of the seven terms rated in base wines separated wines high in tropical fruit, vanilla/butter, floral, and peach/melon from those low in these terms on the first PC (Fig. 2), while the second PC contrasted wines high in apple and citrus from those low in those attributes. In contrast to the configuration observed in Figure for the base wines, the sparkling wines were not clustered by variety, region of origin, winery, or by color of the grapes. Comparison of base and sparkling wine aromas: Each of the seven terms rated in the base and sparkling wines varied highly significantly between the two wine types (p < 0.00) and, with the exception of floral (NS), all terms varied significantly across the 56 wines (p < 0.00 for all except peach/melon p < 0.05) (data not shown). Visual inspection of the differences between =< in v (N to n_ - =< (N to n Citrus Wines. //~ Berry Peachl~d Tropical Mel n"ll:ruit/ [] Chardonnay o Pinot blanc Pinot Meunier Pinot noir [] [] I t (... r i ~ I.....> [] -0.25~'~ [] o o I PC (64%) Vanilla/Butter Fig.. Projection of the attributes on principal components I and II from principal component analysis of the judge averages for the 28 base wines. Aroma Ioadings (vectors) and wine factor scores (points). Wines. Apple n Chardonnay o Pinot blanc Citrus ~" / Pinot Meunier /,, Pinot noir 0.s-- Floral ~" Melon ~'~ / ~ _ Berry E Tropical, ob!::!0~ ~ ~~. II, ". ~ fr,,it i i er i PC (44.9%) Fig. 2. Projection of the attributes on principal components I and II from principal component analysis of the judge averages for the 28 sparkling wines. Aroma Ioadings (vectors) and wine factor scores (points).

4 292- DE LA PRESA-OWENS et al. Table 3. Summary of analyses of variance of main effects: variety, type of wine and wines (nested withing variety), F ratios and degrees of freedom (df). Attributes Variety Wine Type Variety Wine x type (var.) x type Berry 6.60**.63 ns 5.34*** 7.90***.48 ns Peach/Melon 0.30 ns.22 ns 6.70"**.3 ns.66" Green apple 3.82*.5 ns 25.37*** 4.6".39 ns Tropical 0.3 ns 2.25* 62.2"** 0.65 ns.2 ns Citrus 2.40 ns.78 ns 48.33*** 2.66 ns.49 ns Floral 4.54*.90 ns 33.63*** 8.03*** 0.60 ns Vanilla/Butter 5.83** 0.94 ns 4.2"** 5.59** 3.55*** df indicate significance at p < 0.05, p < 0.0, and p < 0.00, respectively. the configurations for base and sparkling wines shown in Figures and 2, suggests that the aromas of the varietal base wines were modified in different ways during the secondary fermentation. Consistent with this, significant Variety Type interactions were found for berry, apple, floral and vanilla/butter (p < 0.05 to p < 0.00) (Table 3). To test the fit of the two wine configurations, the RV coefficient was calculated. A normalized RV value (NRV) of 0.32 was found in the permutation test, confirming the lack of correspondence between the base and sparkling wine configurations. (An NRV value greater than 2.0 is required for a significant fit). These results confirm that the changes in aroma occurring Difference between and wines ~,.5 Berry I [] Chardonnay Peach/aelo[i ~ I o Pinot blanc I~ ~ / I Pinot Meunier ~, ~Tropic~il I mpinotnoir \ Ifruit / o I g [] ~~/: mo [] I Apple / ~. ~ ~ / // IA Floral [] Vanilla/Butter / PC (64.5%) Fig. 3. Projection of the attributes on principal components I and II from principal component analysis of the differences in term ratings between each sparkling and base wine. Aroma Ioadings (vectors) and wine aroma difference factor scores (points). during production of sparkling wine varied differently for either individual wines or different varieties. This means that the profiles of the base wines do not permit prediction of the sensory properties of the sparkling wines after 8 months of lees aging. A PCA of the difference in attribute ratings between sparkling and base wines was performed to determine patterns in the changes in aroma occurring during the secondary fermentation. Similar to the PCA of the base wine data, the first PC separated the wines made from red and white varietal grapes (Fig. 3). The first PC was highly correlated with vanilla/butter and berry and negatively correlated with citrus, apple and floral. From the PCA it can be inferred that there was an increase in vanilla/butter from base to sparkling wine for both white varieties (Chardonnay and Pinot blanc) while there was an increase in citrus, apple, and floral for the red variety wines during the second fermentation in the bottle. No effect of region or winery was apparent in visual inspection of the PCA space (Fig. 3). These inferences were confirmed by the ANOVA of main effects of variety and wine type (base/sparkling) (Table 3) and are illustrated in Figure 4 where the varietal mean ratings are plotted for base and sparkling wines. Four aroma terms varied significantly across variety: berry and vanilla/butter, apple and floral. All attributes were significantly more intense in the sparkling wines, than the corresponding base wines with the exception of berry which showed the opposite pattern. The secondary fermentation increased the intensity of vanilla/butter in the white varietal wines (Chardonnay and Pinot blanc), while no significant difference occurred in the red varieties (Pinot noir and Pinot Meunier). Conversely, the berry aroma decreased significantly in the red varietals, while no significant difference was observed for the whites. Citrus, tropical fruit, and peach/melon aromas were significantly higher in sparkling wines for all varietals, while only for the red varietals was a significant increase in floral and apple produced during the secondary fermentation. For the first time, the effect of the secondary fermentation has been shown to be different for the four major varietals used in sparkling wine production. Due to the extensive training of the judges in both studies, it is unlikely that this is the result of the use of different judges for evaluation of the base and sparkling wines. Although the standards for the terms were prepared slightly differently for the studies, the concept of each attribute may have been quite similar. However, there is no way in which to prove this. Inclusion

5 T EFFECT OF METHODE CHAMPENOISE ON AROMA m 293 [~ 3.5 Berry,,,I... Vanilla -l- 2.5 >,,, 2 " ,-p =,..... Peach/Melon "I =El ' ' ~ r..~.~ * '"IN N El ~~ ' m~ N~]!!!~! BI! I. W I~ il W~ ,I ~... ~... ~ I,.... : 3- Citrus i 2.6 :" 2 m.5 0 Chardonnay Plnot blanc Plnot Plnot nolr 2.5 Apple i TI Floral >" 2 it t- =.s J......J t I I meunier 3.5 ~-m,, [m. _. Tropical Fruit,., ;... ~... Chardonnay Pinot blanc Pinot meunier....i... Pinot noir Fig. 4. Mean values for the intensity of base and sparkling wines for each variety for each aroma term. The barbells denote the 95% confidence interval. (Where there were 2 Chardonnays, 3 Pinot blancs, 4 Pinot Meuniers and 9 Pinot noirs, for base wines n = 2 judges x 2 reps x number of wines per variety; for sparkling wines n = 7 judges x 3 reps x number of wines per variety.

6 294- DE LA PRESA-OWENS et al. of one of the base wines with the sparkling wines descriptive analysis would not have standardized the analysis for two reasons: () the base wine would have been 8 months older, (2) the contrast between the base wine and the sparkling wines would have overshadowed other differences among the wines. The secondary fermentation in sparkling wines produces the carbon dioxide bubbles associated with this beverage. However the primary changes in flavor are thought to arise from autolysis of yeast which occurs during aging on the lees which are reported to slow after two years [2]. Informal reports from both French and Californian sparkling winemakers suggest that changes due to yeast autolysis develop first in white varieties and may require up to three years for development in red varietals. In this study, after 8 months on the lees, the absolute difference in intensity ratings was larger for the red wines than the white (Fig. 4). However, the size of the over all change in aroma cannot be estimated from this type of study since no overall judgements of aroma intensity were made. Conclusions wines for sparkling wine production are chosen for their lack of distinctive aromas. However, a separation among base wines according to color of the cultivar was observed. The major differences in aroma between red and white base wine varieties were the characterization of Chardonnay and Pinot blanc wines as higher in intensity of floral, citrus and apple notes, while Pinot Meunier and Pinot noir base were higher in berry and vanilla/butter. The secondary fermentation of these base wines by M~thode Champenoise produced wines which had higher intensity ratings for all attributes except berry. 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